Viking EDR-2 Tape

The Viking EDR-2 Tape data are obtainable from NSSDC website. One is a program to convert from Science Analysis of Seismometer Data (SASEIS) Tape to ASCII data, and the others are the converted ASCII data:
  • NSSDC ID: PSPG-00472 ... Seismic Data Record Format Program
  • NSSDC ID: PSPG-00070 ... Seismic Data Records
These data are archived as NSSDC Archival Information Package (AIP) [1], and a user must interpret the AIP structure to access the program and data referencing AIP attributes.

Seismic Data Record Format Program (PSPG-00472)

The PSPG-00472 is a PL/I program to convert from SASEIS EDR Tapes to ASCII data (PSPG-00070). The PSPG-00472 is a text file in not ASCII code but EBCDIC-US code [5]. The program 'dat2pl1.c' is a program in C to obtain the PL/I program from PSPG-00472. This program interprets NSSDC AIP structure and converts EBCDIC-US code to ASCII code.
  • dat2pl1.c ... sample program to convert from PSPG-00472 to PL/I source code
    Compile:
    $ gcc -o dat2pl1 dat2pl1.c
    
    Execution:
    $ tar xvf (somewhere)/PSPG-00472_DD029660.tar
    $ ./dat2pl1 PSPG-00472_DD029660.dir/DD029660_F1.DAT
    	      
  • EDRFMT ... extracted PL/I program

See also Seismic Data Record Format Program.

Seismic Data Records (PSPG-00070)

Seismic Data Records is the actual data obtained by the Viking Lander 2 seismometer. The detail format description is written in Viking Lander 2 Seismic EDR-2 [2]. Note that two characters '¬' and '|' are lost in the original ASCII data, which means the extracted ASCII data are not correctly restored even if the AIP structure is correctly interpreted. These two characters are used to describe the length of line. The 'preformat.pl' program recovers these lost characters considering line pattern and generates pre-formatted ASCII data. '¬' does not exist in ASCII code, '∧' is used in the pre-formatted ASCII data instead. The pre-formatted ASCII data follows EDR-2 documents, but it is difficult to use without reformatting. The program 'reformat.pl' performs the conversion to a user-friendly ASCII format. The following files are not correctly converted:
  • DD031190_F1.DAT ... Remove invalid characters at the head of the file.
  • DD032029_F1.DAT ... Data start at the middle of the buffer (Buffer Number 1310).
  • DD032352_F1.DAT ... Data start at the middle of the buffer (Buffer Number 1000).
  • DD032357_F1.DAT ... Data start at the middle of the buffer (Buffer Number 1010).
  • DD032671_F1.DAT ... Data start at the middle of the buffer (Buffer Number 1000).
  • DD032675_F1.DAT ... Data start at the middle of the buffer (Buffer Number 1710).
  • DD032681_F1.DAT ... Data start at the middle of the buffer (Buffer Number 1010).

See also Sesmic Data Records.

Relationship between data and softwares

Last Modified: 19 June 2017